package com.hafu.util; public class StringUtil{
    public static boolean isEmpty(String str){
        return   str   ==null    ||str.trim().length()==0;
    }
    public  static  void  main(String[]args){ String  s1=null;
        String  s2="";
        System.out.println(s2); System.out.println(s1);
        System.out.println(isEmpty(s1)); System.out.println(isEmpty(s2));

    } }